1. Field of the Invention
This invention pertains generally to the construction and operation of sieves of the bend type for the separation and sizing of solid particles dispersed in a liquid medium as a slurry and, more particularly to such apparatus and methods that are applicable to the coal and mineral industry to produce two products, one comprising fine particles and the other coarse particles complying with size and quality specifications.
2. Related Art
Heretofore, various types of separating apparatus, such as sieve bends, and methods have been used for the separation of fine solid particles from a liquid medium in which they are dispersed. Such apparatus includes simple sieve racks, hydrocyclones, sieve bends and other types of apparatus making use of hydraulic separation. The coal industry, for example, makes use of sieve bends for the treatment of coal slurries. For the purpose of producing products which comply with size specifications, special techniques have been employed, such as the use of heavy or magnetic particles intermixed with the particles being subjected to separation. Such apparatus and methods have certain limitations and disadvantages, including difficulty in meeting specifications requiring a particular particle size. Furthermore, they are unable to deal effectively with sulphur or clay which may be attached to some of the particles, particularly the larger ones. In general, it may be said that the coal industry is in need of simple apparatus and methods which will make it possible to produce a product consisting of fine coal particles which comply with size specifications and are substantially free of contaminants such as sulphur.